Adenosine receptor inhibition attenuates the suppression of postexercise cutaneous blood flow
Bibliographic record
Abstract
Key points Skin blood flow (SkBF) is an important avenue for heat loss; however, it is rapidly suppressed after exercise despite persistently high core and muscle temperatures. This has been ascribed to altered active vasodilation; however, recent work has identified a role for adenosine receptors in the decrease in SkBF following passive heating. In this study, we examined whether adenosine receptors are involved in the postexercise regulation of SkBF by infusion of 4 m m theophylline (a non‐selective adenosine receptor antagonist) via microdialysis. We show that adenosine receptors have a major role in modulating postexercise SkBF, as evidenced by a marked elevation during theophylline infusion compared to a control site. These results help us to better understand the mechanisms underlying the postexercise reduction in SkBF and subsequently heat loss which is associated with heat‐related illness and/or injury. Abstract The time‐dependent contributions of active vasodilation (e.g. nitric oxide) and noradrenergic vasoconstriction to the postexercise suppression of cutaneous perfusion despite persistent hyperthermia remain unknown. Moreover, adenosine receptors have been shown to mediate the decrease in cutaneous perfusion following passive heating. We examined the time‐dependent modulation of nitric oxide synthase, noradrenergic vasoconstriction and adenosine receptors on postexercise cutaneous perfusion. Eight males performed 15 min of high‐intensity (85% ) cycling followed by 60 min of recovery in temperate ambient conditions (25°C). Four microdialysis probes were inserted into the forearm skin and continuously infused with: (1) lactated Ringer solution (Control); (2) 10 m m N G ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME; nitric oxide synthase inhibitor); (3) 10 m m bretylium tosylate (BT; inhibitor of noradrenergic vasoconstriction); or (4) 4 m m theophylline (THEO; adenosine receptor inhibitor). Cutaneous vascular conductance (CVC) was expressed as a percentage of maximum and was calculated as perfusion units (laser Doppler) divided by mean arterial pressure. End‐exercise CVC was similar in Control, THEO and BT ( P > 0.1), but CVC with l ‐NAME (39 ± 4%) was lower than Control (59 ± 4%, P < 0.01). At 20 min of recovery, Control CVC (22 ± 3%) returned to baseline levels (19 ± 2%, P = 0.11). Relative to Control, CVC was reduced by l ‐NAME for the first 10 min of recovery whereas CVC was increased with BT for the first 30 min of recovery ( P < 0.03). In contrast, CVC with THEO was elevated throughout the 60 min recovery period ( P ≤ 0.01) compared to Control. We show that adenosine receptors appear to have a major role in postexercise cutaneous perfusion whereas nitric oxide synthase and noradrenergic vasoconstriction are involved only earlier during recovery.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".